The present invention relates to a device for measuring small lengths or distances. Such devices may include a sensing tip which is movable along the length to be measured, a transducer for converting the movements of the sensing tip into a corresponding electric signals, and an indicator for indicating the electrical signals.
Devices of this kind, for measuring small lengths or sections, have been known for some time. For example, a device of this type, in the form of a mechanically inductive transducer, is shown in FIG. 9 of German patent specification No. 11 00 978. The sensing tip of this prior device moves an iron core in a system of coils. The coils are enclosed in a measuring bridge which supplies an electric output signal. The output signal is dependent on the movements of the sensing tip. The relatively heavy weight of the iron core being moved, however, substantially reduces the speed at which the device may measure distances. In addition, the weight of the iron core subjects the sensing tip to a great deal of wear, and this wear becomes even more acute the finer, or more delicate, the sensing tip is. Such delicate sensing tips, however are required to properly sense the fine structure of a surface. Another disadvantage of the foregoing device is its limited linearity, especially when it is executing large measuring strokes.